Improved double screw



uiten tutes gutem ffirr.

ELIJAH S. PIERCE, HARTFORD, CONNECTICUT.

' Letters Patent No. 71,909, dated December 10, 1861.

IMPROVED DOUBLE SCREW.

tte Stimuli: tefrmh tu im time 3mm what :mh making part nt the :mmf

TO ALL WHOM IT MAY CONCERN:

Be it known that I, ELIJAH S. Pinson, of Hartford, in the county of Hartford, and State of Connecticut, have invented a new and useful article of manufacture, being an Improved Double Screw; and do hereby declare that the `following is a full, clear, and exact description of the same, reference being had to the accompanying drawings, and to the letters of reference marked thereon.

Figure 1 shows two views of the improved double screw, with ahead having slots or nicks out in opposite sides for the purpose of turning-it. A

Figure 2 shows two views of the improved double screw, with the head flattened on opposite sides for theA same purpose.

A A, Ste., are the screw-threads at each en d of the double screw. B B, dto., are the heads. C C, dac., are sections in the middle of the heads. My invention consists in providing a. double screw with an intermediate head for the purpose of turning it,

and also for the purpose of preventing one end ofthe screw from penetrating too far when the double screw is` used for uniting two diferent kinds of wood, or other material, when one is softer and morel easily penetrated l than the other.

The improved double screw is made b y striking up thel head oula. wire of the proper size, and cutting the threads in the ordinary manner for single screws. It can also be made by turning down to the proper shape and size from a larger rod or wire. Two ordinary screws can also he united together to obtain the same form. 'The improved double screw is useful in attaching handles or ornaments to drawers or doors, `and for any other purposes to which straight wires with a. thread out at both ends are now applied.

With the improved double screw, no especial care need be taken in preparingV the holes for its reception,

as it will enter each of the two parts to be'joined as far as the head, which will prevent 4farther entrance when it has reached the surface, so that when the two parts are brought together, as in screwing on a knob, the head will remain `between the two parts united, and the screw will enter each of the two parts equally, if the branches of the screw are of the same length. Were it not for the head, the screw` would turn more easily, and farther into the softermaterial.

Claim. I claim the double screw herein described and shown, as a new article of manufacture.

E. S. PIERCE.

Witnesses:

L. WooDnoUsE, Trino. G. ELLIS. 

